viven44 Posted February 22 Author Share Posted February 22 Have a look at this guy (Mike's) video where I start at about 15:26 Can you see where the water pump was? Does it look all ribbed with voids behind the impeller? All I can say is the discussion above is quite interesting... If I understand things the right way... can vacuum advance on a distributor can be tuned precisely using a vacuum orifice i.e. recurving it by using less or more vacuum ? The parallel between electrons and air (or lack thereof) is interesting as well. Voltage equals pressure with which electrons are pushed. Voltage drop would occur across a resistor with current flow. The larger the current flow, the larger the voltage drop. Heat would be dissipated proportional to the amount of voltage drop / current flowing. With Air, that would mean a restrictor would reduce air pressure past the restrictor, but we are talking vacuum. That means there would be more vacuum (less loss) at the inlet (side connected to VCV), but less air being vacuumed out of the outlet (connected to distributor). Interested to see what is found out of Gary's experiment Link to comment Share on other sites More sharing options...
viven44 Posted February 22 Author Share Posted February 22 Have a look at this guy (Mike's) video where I start at about 15:26 Can you see where the water pump was? Does it look all ribbed with voids behind the impeller? Yep! I am picking up the water pump plate, timing set from Summit. I am also replacing the water pump with a gates unit. The old water pump and any work done with it, I just don't trust anymore. I am not a parts swapper and hate doing that blindly, but the water pump is $30 and I don't want to go back and re-do any of this for a while. Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted February 22 Share Posted February 22 Yep! I am picking up the water pump plate, timing set from Summit. I am also replacing the water pump with a gates unit. The old water pump and any work done with it, I just don't trust anymore. I am not a parts swapper and hate doing that blindly, but the water pump is $30 and I don't want to go back and re-do any of this for a while. I can't really blame you. Link to comment Share on other sites More sharing options...
viven44 Posted February 22 Author Share Posted February 22 Is that going to prove that you can pump fast enough to keep up with the restriction? Jets are jets. It's pretty much all about how much it can flow at a given depression. And that's dependent on the size of the hole. (and how smooth it is) Agree, for the experiment to work you need a constant source of vacuum that is constantly replenished. The MityVac won't provide that. Link to comment Share on other sites More sharing options...
Gary Lewis Posted February 22 Share Posted February 22 All I can say is the discussion above is quite interesting... If I understand things the right way... can vacuum advance on a distributor can be tuned precisely using a vacuum orifice i.e. recurving it by using less or more vacuum ? The parallel between electrons and air (or lack thereof) is interesting as well. Voltage equals pressure with which electrons are pushed. Voltage drop would occur across a resistor with current flow. The larger the current flow, the larger the voltage drop. Heat would be dissipated proportional to the amount of voltage drop / current flowing. With Air, that would mean a restrictor would reduce air pressure past the restrictor, but we are talking vacuum. That means there would be more vacuum (less loss) at the inlet (side connected to VCV), but less air being vacuumed out of the outlet (connected to distributor). Interested to see what is found out of Gary's experiment Gary wasn't planning to do the experiment as he's installing seats and painting a console. But I don't think you can tune a dizzy via a restriction. I'm back to the electricity analogy - you only have a drop across a resistor/restriction if there is flow through it. And my experience is that a good vacuum can doesn't leak. So I'm still at a loss as to how this works. I'm missing something. Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted February 22 Share Posted February 22 Gary wasn't planning to do the experiment as he's installing seats and painting a console. But I don't think you can tune a dizzy via a restriction. I'm back to the electricity analogy - you only have a drop across a resistor/restriction if there is flow through it. And my experience is that a good vacuum can doesn't leak. So I'm still at a loss as to how this works. I'm missing something. About the only way you can tune a distributor, is on a Sun machine. The restriction damps the changing vacuum. But there has to be some kind of bleed. Link to comment Share on other sites More sharing options...
viven44 Posted February 22 Author Share Posted February 22 Gary wasn't planning to do the experiment as he's installing seats and painting a console. But I don't think you can tune a dizzy via a restriction. I'm back to the electricity analogy - you only have a drop across a resistor/restriction if there is flow through it. And my experience is that a good vacuum can doesn't leak. So I'm still at a loss as to how this works. I'm missing something. I think there will always be some flow, we are talking only 20" Hg or less, which is several orders below absolute vacuum... Edit: Also what happens when the vacuum advance is not in effect (when throttle is changed).. it has to go somewhere.. does that count as a "bleed" Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted February 22 Share Posted February 22 I think there will always be some flow, we are talking only 20" Hg or less, which is several orders below absolute vacuum... Edit: Also what happens when the vacuum advance is not in effect (when throttle is changed).. it has to go somewhere.. does that count as a "bleed" The diaphragm couldn't resist that. We're not talking about an electron microscope, it's a dang distributor found in hundreds of millions of vehicles Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted February 22 Share Posted February 22 I think there will always be some flow, we are talking only 20" Hg or less, which is several orders below absolute vacuum... Edit: Also what happens when the vacuum advance is not in effect (when throttle is changed).. it has to go somewhere.. does that count as a "bleed" The springs in the distributor pull the advance back towards zero. The restriction keeps the plate from being able to move too quickly. But the restriction also must provide some kind of limit to manifold vacuum. We see that in how it's implemented in the system Link to comment Share on other sites More sharing options...
viven44 Posted February 22 Author Share Posted February 22 Is that going to prove that you can pump fast enough to keep up with the restriction? Jets are jets. It's pretty much all about how much it can flow at a given depression. And that's dependent on the size of the hole. (and how smooth it is) By the way here is Big Blue 2WD’s vacuum diagram. Simplest one I’ve seen. 460/non-AC/no cruise control cab. Literally every single vacuum control device is present but some things are capped off. EGR is hooked up, no pinging. Maybe it’s stuck open partially. Dist is connected to Ported vac from Edelbrock. The previous owner and I have hauled and abused this truck this way for a long time. The previous owner even made a round trip from Texas to Washington .. Should I get it back to how it’s supposed to be ?? http://www.garysgaragemahal.com/uploads/6/5/8/7/65879365/laughing-25-x-25_orig.gif Link to comment Share on other sites More sharing options...
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